This smooth surface reduces the collection of dirt which might otherwise lead to tracking failure. The thermosetting modified epoxy resin provides excellent arc resistance and minimizes flashover. Poly Glas 76881 is an electrical grade, parallel glass banding tape, impregnated with an uncured, high temperature, modified epoxy varnish. The glass fibers used are specially treated to improve moisture resistance. During cure, resin flow fills voids and air spaces, producing a homogeneous laminate, with a smooth resin rich surface.